The present invention relates to vehicles, particularly of the type which are self-loading and which are capable of transporting and discharging the load which the vehicle takes on.
Such a vehicle will have an elongated frame at one end of which is the propelling structure for providing the required traction and steering of the vehicle while at the other end there is the structure for receiving, carrying, and discharging the load.
Conventionally, in order to transport loads of any desired characteristics from one location to another it is required to have a wheeled loading vehicle forming a wheel loader and a separate transporting vehicle which receives the load from the wheel loader. One of the drawbacks encountered when using such a wheel loader is that the friction between the wheels of the loader and the surface engaged thereby exerts a significant influence on the pushing force of the loader and thereby on the extent to which its scoop can be filled. Thus, under certain operating conditions the wheels of the loader engage a slippery soft surface which detracts undesirably from the friction required for efficient operation of the loader. In addition, the wheels tend to sink into such a soft surface with an accompanying increase in the resistance to rolling of the wheels. A further drawback of such wheel loaders arises from difficulties encountered when working on sloping terrain and when encountering unfavorable weight distribution.
Also, when utilizing separate loaders and transporting conveyance, there is an unavoidable and costly standing time when a vehicle which is to transport a load must wait until it receives the load. Such expensive waiting time is particularly noticeable in the event that, for example, the loader breaks down while a vehicle waits its turn to be loaded. Under such conditions the operating or working cycles of several vehicles are undesirably interrupted.
Furthermore, wheel loaders of the above type can only operate when there is sufficient space for the loader to move around both with respect to the load as well as with respect to the vehicle which is to receive the load. As a result when operating in relatively confined spaces, such as in the interior of a tunnel, significant disadvantages are encountered with such conventional procedures and structures.
One of the most serious drawbacks encountered in connection with conventional wheel loaders, whether of the front-end loading type or rear-end loading type, resides in the considerable lack of stability of such conventional wheel loaders during travel thereof. This results from the fact that the bucket which receives the load in such conventional wheel loaders is situated beyond the wheelbase. As a result, the loaded bucket tends to tilt the vehicle, about one of its axles, and when it is remembered that such wheel loaders conventionally operate on rough terrain which may be sharply inclined, it is apparent that there is considerable instability in the travel of such conventional wheel loaders. Therefore, conventional wheel loaders can only operate within an exceedingly limited range, in the immediate vicinity of the load which is to be picked up, requiring the vehicle which is to be loaded to be situated quite close to this load. Up to the present time it has not been possible to provide wheel loaders capable of carrying a load in a safe manner through a substantial distance to a vehicle which is to receive the load, so that of necessity the latter vehicles must be situated quite close to the load, even though wheel loaders are utilized.
In addition, considerable energy is expended in an undesirable manner in operating conventional wheel loaders. Thus, while the buckets of certain types of wheel loaders may be of substantial magnitude, so as to be capable of carrying a considerable load during a single operation, nevertheless the load-carrying capacity of all known conventional wheel loaders is only a fraction of the weight of the wheel loader itself.